If the highway of the future is filled with self-driving cars, cities will be able to do something that only happens in their dreams: increase the number of vehicles a highway can handle without building expensive new highways or adding more lanes.

How? When cars become adept at communicating with one another through technology they will be able to drive on the same strip of highway, really close together (think of it like terrible traffic jam, except you're actually moving fast or a flock of birds that pollutes). Combine talking cars with cars that drive themselves and you're looking at a super efficient highway.

A new paper presented by Columbia University's Patcharinee Tientrakool at the Institute of Electrical and Electronics Engineers (IEEE) conference, compares the safe driving distance and resulting highway capacity for three scenarios: on highways with 100 percent manual cars, 100 percent cars with sensors that automatically brake, and 100 percent self-driving cars. Here are the results of Tientrakool's research:

If 100 percent of cars use vehicle-to-vehicle communication highway capacity increases by 43 percent. If all cars are also autonomous and talk to each other that capacity increases by an impressive 273 percent.

At this point, vehicle-to-vehicle communication is the next innovation in vehicle technology that, in the near future, is most likely to see something close to the 100 percent use hypothesized in the research. Talking cars will moderately (though not insignificantly) increase highway capacity, as well as keep drivers safe. And while self-driving cars might be a long way out (though Google is narrowing the gap), it's clear that when they are widely implemented it will be a game changer. Not only will they make highways more efficient and save on gas by making traffic jams obsolete, but, at least from what we've observed so far, they will be really safe.

With all the money that's saved by not building new highways (or widening them) maybe more of the transportation budget can go to transit and other alternative transportation options.